Subnet Pro allows you to quickly calculate the number of hosts a given Classless Internet Domain Routing (CIDR) mask will provide, or put in the number of hosts you need and it will tell you the mask, both in CIDR and dotted decimal notation. You can generate a comma-delimited list of IP addresses that you can send via email to paste into a spreadsheet for managing the IP address range. Subnet Pro also displays the mask in the inverse wildcard notation for easy conversion when constructing Access Control Lists (ACLs).

Subnet Pro does not require an Internet connection unless you wish to email the IP address range and does not nag you about not being connected to the Internet.